Cable systems have often been used as safety systems for roadside barriers or as tie-down measures for securing equipment such as antennas, towers, or safety fences/netting. Using cable systems for these purposes requires that the cables be maintained in constant tension and not break loose. If not, they would fail as a securing mechanism. The cable used in these systems is typically manufactured from heavy gauge steel wire, rated to maintain a desired loading. Unexpected failure of the cable safety system can result in significant property damage to the item being secured, as well as potential injury or fatality to bystanders.
Prior art mechanisms that release a cable from its anchor have traditionally relied on the fracture of a post or support. In these mechanisms, the cable is passed through the base of a post such that when the post fractures on impact, the cable is freed from its anchor.
As previously mentioned, roadside barriers have been known to use cable safety systems as guardrails. In such an arrangement, at least one cable is supported by relatively weak steel posts. The steel cables are pre-tensioned with an initial load, and are anchored at both ends of the system. The anchoring typically occurs along a surface such as the roadside or ground. When an errant vehicle obliquely impacts the system, which is most commonly a three cable system, the cables have sufficient tension in them to absorb the impact and redirect the vehicle back towards the driving surface, effectively shielding the roadside hazard and increasing the safety of the vehicle operator. This is especially important on roads that do not have other types of barriers that could perform similar functions (i.e. curbs, concrete walls). Numerous fatalities and injuries have been attributed to vehicles leaving the road and either rolling or entering opposing traffic lanes, thereby potentially endangering other motorists, as well as the occupants of the errant vehicle. The support posts alone offer very little resistance to the impacting vehicle.
While these conventional systems have proven successful, they also possess shortcomings. For example, these systems are typically employed where deemed necessary by traffic officials or government regulations. As a result, they are not used along all roadsides, but instead in sections. At the ends of these sections, the cables are anchored to the surface. Accordingly, the cables taper from their maximum height between the support posts to their minimum height at the surface. Since these conventional cable systems are not designed to give way, a vehicle striking the cable system longitudinally, or in line with the taper of the cables, is likely to ride up the tapered cables and initiate a rollover, thereby causing serious damage to the vehicle and severe, if not fatal, injuries to any passengers. This has become a more prevalent event as more roadside cable systems are now being installed with ends tangent to the roadway, instead of being flared away from it.